An organic light-emitting diode (OLED) display panel is generally formed with a stacked structure of a glass substrate, an indium tin oxide (ITO) anode, an organic light emitting layer (emitting material layer), a cathode and so on. The organic light emitting layer is sandwiched between the ITO anode, which is thin and transparent, and the metal cathode. When holes from the anode and electrons from the cathode combine in the organic light emitting layer, the organic material in the organic light emitting layer will be excited to emit light. Active matrix organic light-emitting diode (AMOLED) display panels are a kind of OLED display panels. Compared to conventional liquid crystal display panels, AMOLED panels have characteristics of faster response speed, higher contrast, wider viewing angle, etc., and have wide application prospective.
A conventional manufacturing process for an OLED display panel may broadly include the following two steps:
1. An active matrix is formed on a substrate.
2. An array of organic light emitting devices is produced and packaged, wherein the organic light emitting devices include ITO anodes, a pixel defining layer on the anodes, organic electroluminescent layers and cathodes.
The organic electroluminescent layers are sandwiched between the anodes and the cathodes to form a sandwich structure. The pixel defining layer acts to define the size of pixels and the anodes, and to ensure insulation between the anodes and the cathodes.
FIG. 1 is a structurally schematic view showing an active-region pixel prior to fabrication of a pixel defining layer in prior art. In the figure, 101a˜101b denote scan lines, 102a˜102b denote data lines, 105a denotes a driving power line; 109 denotes a switch transistor; 110 denotes a driving transistor; 103a denotes an active area, which is formed of a semiconductor material, such as monocrystalline silicon, polysilicon, indium gallium zinc oxide (IGZO), etc.; 104a denotes a connecting line for connecting the switch transistor 109 and the driving transistor 110; and 106a denotes a transparent electrode. Based on FIG. 1, FIG. 2 is a structurally schematic view further showing the pixel defining layer. The region 107a in FIG. 2 is the pixel defining layer within one pixel, and a region DA in the pixel defining layer is the region for display in the corresponding pixel.
The material for forming the pixel defining layer is usually photoresist. The pattern of the pixel defining layer is generally formed by using a photolithography process in prior art, and the mask plate used for patterning is generally a mask plate specifically designed for the pixel defining layer. Meanwhile, during photolithography, one positioning process is required for precise positioning of the mask plate so as to form the pixel defining layer accurately.
As can be seen from the above, upon production of the pixel defining layer in prior art, a specific mask plate is required and one positioning process is required, and therefore the producing flow is relatively complex and the production costs are relatively high; moreover, because one positioning process is required, yield of display panels can be affected by precision of the positioning.